Add test for FolderPropertyLoader class (#418)

* Add test for FolderPropertyLoader class

* Change freestyleproject object name from project to j

* Make test results clearer by checking decision logger results

Since the API provides a decision logger and an adjustment was made to
the decision logger in the test setup, let's use that decision logger
to make the test expectations clearer and the assertions more precise.

Initialize the JenkinsRule only once and create the project only once,
since neither are modified substantially for the test.

Use a more precise name for the methods that are called before test
execution so that later readers understand the purpose of the methods
without reading their contents.

Use the common name 'j' for the JenkinsRule and a more descriptive name
for the FreeStyleProject variable name.

---------

Co-authored-by: Mark Waite <[email protected]>

src/test/java/jenkins/advancedqueue/jobinclusion/strategy/FolderPropertyLoaderTest.java

@@ -0,0 +1,86 @@
+package jenkins.advancedqueue.jobinclusion.strategy;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.hasItem;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+
+import com.cloudbees.hudson.plugins.folder.Folder;
+import hudson.model.FreeStyleProject;
+import java.util.ArrayList;
+import java.util.List;
+import jenkins.advancedqueue.DecisionLogger;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.jvnet.hudson.test.JenkinsRule;
+
+public class FolderPropertyLoaderTest {
+
+    @ClassRule
+    public static JenkinsRule j = new JenkinsRule();
+
+    private static Folder folder;
+    private static FreeStyleProject project;
+    private DecisionLogger decisionLogger;
+    private List<String> loggedMessages;
+
+    @BeforeClass
+    public static void createJob() throws Exception {
+        folder = j.createProject(com.cloudbees.hudson.plugins.folder.Folder.class, "testFolder");
+        project = folder.createProject(FreeStyleProject.class, "testProject");
+    }
+
+    @Before
+    public void createDecisionLogger() throws Exception {
+        loggedMessages = new ArrayList<>();
+        decisionLogger = new DecisionLogger() {
+            @Override
+            public DecisionLogger addDecisionLog(int indent, String log) {
+                loggedMessages.add(log);
+                return this;
+            }
+        };
+    }
+
+    @Test
+    public void getJobGroupName_returnsGroupName_whenJobGroupIsEnabled() throws Exception {
+        JobInclusionFolderProperty property = new JobInclusionFolderProperty(true, "TestGroup");
+        folder.getProperties().add(property);
+
+        String result = FolderPropertyLoader.getJobGroupName(decisionLogger, project);
+
+        assertEquals("TestGroup", result);
+        assertThat(loggedMessages, hasItem("JobGroup is enabled, with JobGroup [TestGroup] ..."));
+    }
+
+    @Test
+    public void getJobGroupName_returnsNull_whenNoJobGroupProperty() throws Exception {
+        String result = FolderPropertyLoader.getJobGroupName(decisionLogger, project);
+
+        assertNull(result);
+        assertThat(loggedMessages, hasItem("No match ..."));
+    }
+
+    @Test
+    public void getJobGroupName_returnsNull_whenJobGroupIsDisabled() throws Exception {
+        JobInclusionFolderProperty property = new JobInclusionFolderProperty(false, "TestGroup");
+        folder.getProperties().add(property);
+
+        String result = FolderPropertyLoader.getJobGroupName(decisionLogger, project);
+
+        assertNull(result);
+        assertThat(loggedMessages, hasItem("No match ..."));
+    }
+
+    @Test
+    public void getJobGroupName_returnsNull_whenParentIsNotFolder() throws Exception {
+        FreeStyleProject standaloneProject = j.createFreeStyleProject("standaloneProject");
+
+        String result = FolderPropertyLoader.getJobGroupName(decisionLogger, standaloneProject);
+
+        assertNull(result);
+        assertThat(loggedMessages, hasItem("No match ..."));
+    }
+}